Refrigerant storer for steam operated refrigeration system



Feb. 21, 1967 L. H. LEONARD, JR 3,304,998

REFRIGERANT STORER FOR STEAM OPERATED REFRIGERATION SYSTEM Original Filed June 23, 1964 INVENTOR.

BYW XK i ATTORNEY.

LOUIS H. LEONARD, JR.

United States Patent 4 Claims. (Cl. 165-1) This application is a division of my copending application Serial No. 377,315 filed June 23, 1964, entitled Heating and Cooling System, and relates broadly to a heating and cooling system. More particularly, this invention relates to a heating and cooling system employing a re frigeration apparatus. Still more particularly, this invention relates to a system of the kind described wherein improved refrigerant handling means are provided.

My copending patent application for a Heating and Cooling System, Serial No. 377,319, filed June 23, 1964, discloses a system for heating and cooling wherein a steam condenser is purged of noncondensible vapor, such as refrigerant vapor, to control operation of the system and to provide efficient heating of a load to be heated. The refrigerant vapor is removed from the steam condenser by means of a purge operated by a water driven jet pump. In order to assure optimum operation of the purge system, the temperature of the jet impelling water should be low enough to prevent the purge jet water from flashing in the jet'at the venturi.

During winter heating operation, when cooling is not required, it may be desirable to withdraw the refrigerant from the normal refrigerant circuit, for example, in order to reduce the load on the purge system. It is also sometimes necessary to withdraw the refrigerant in order to service the machine. In order to facilitate shipping the machine pre-charged with refrigerant, thus reducing the overall cost of the equipment when it is installed and ready to operate, some means should be provided to hold the refrigerant out of the refrigerant circuit, as is understood in the art. While the refrigerant may be kept in a tank separate from the machine, contamination of the refrigerant may result and additional time and equipment are necessary, in transferring the refrigerantbetween the machine and a separate container. Furthermore, the use of a refrigerant container separate from the machine does not facilitate factory charging of the machine.

It is a primary object of this invention to provide a new and improved heating and cooling system and a method for handling'andstorin g refrigerant in a refrigeration system.

Another object is to provide a new and improved method of passing refrigerant vapor from a cooler to a refrigerant storage vessel upon stopping normal cooling operation of the system, and providing a temperature in the vesse1 below the saturation temperature corresponding to the vapor pressure of the refrigerant, thereby condensing and retaining the refrigerant in the vessel. A related object is provision for passing the refrigerant from the vessel to the cooler upon starting the system in normal cooling operation.

Still another object is provision of a new and improved heating and cooling system including a cooler having a water sump, a steam condenser for condensing steam and heating a heating medium for circulation to a load to be heated, with steam driven operating means for discharging steam into the steam condenser and for circulating refrigerant through the cooler during cooling operation of the system, a purge system operable upon cir culating impeller water from the sump at a temperature ice below that in the steam condenser for removing noncondensibles from the steam condenser and discharging the water and noncondensibles into the sump, a storage vessel connected with the cooler for the passage of refrigerant from the cooler into the vessel when the operating means is passage of refrigerant from the vessel into the cooler when the operating means for passing steam into the steam condenser to heat the heating medium and to render the operating means inoperative during winter heating operation of the system, and a heat exchanger in circuit during winter heating operation to associate the impeller water and the heating medium returning to the steam condenser to provide an impeller water temperature below that in the steam condenser, thereby effectively preventing flashing of the water in the purge system.

Another object is provision of a new and improved cooling system including a refrigerant circuit, storage means for withdrawing refrigerant from the circuit when the system is inoperative for cooling, and operating means operable for circulating refrigerant through the circuit during cooling operation of the system and providing a pressure in the circuit below that in the storage means for withdrawing the refrigerant from the storage means.

Another object is provision of a new and improved heating system including enclosing means for a heated vapor, the enclosing means receiving a heating medium passing to a load to be heated, a purge system including a jet pump for removing noncondensibles from the steam condenser responsive to circulating impeller water to the jet pump, and a heat exchanger to associate the impeller water and the heating medium returning to the enclosig means to provide an impeller water temperature below that of water in the enclosing means, thereby effectively reventing flashing of the purged water in the purge systerm.

The drawing is a flow diagram of a preferred embodiment of the invention in a heating and cooling system.

The invention is illustrated in the form of a heating and cooling system for providing cooling, heating, or simultaneous heating and cooling. The system is preferably hermetic in that fluids in the system are effectively prevented from escaping and ambient air is kept out of the system. The system may be considered as having a power side including a circuit for the circulation of a power fluid, a refrigerant side including a circuit for the flow of a refrigerant fluid under the influence of operating means driven by the power fluid, with the operation of the system regulated by a control system.

The invention will be described with reference to a preferred power fluid, which is water, and a preferred refrigerant, which is octafluorocyclobutane, commonly referred to as C318 and having a chemical formula C F These fluids are particularly preferred because of their relative immiscibility and because they are inherently highly stable and do not tend to decompose or chemically react with each other or other materials in the system, or cause or promote corrosion or undesirable byproducts. Also, this refrigerant is a relatively noncondensible vapor at the temperatures and pressures at which the power fluid (water) condenses, as well as at the usual ambient atmospheric conditions of temperature and pressure. However, other power fluids and refrigerants having these desired chemical and physical properties may be utilized within the scope of this invention.

As illustrated in the drawing, the power side includes a suitable steam generator 12 having a burner 13 connected with a mixing chamber 14 for mixing a fuel, such as gas, received through a gas line 15 having a modulating flow regulating gas valve 16, and air received through a combustion air line 17 from a blower 18. The steam generator 12 upplies steam at a substantially constant inoperative and for the pressure p.s.i.g., for example) as controlled by a constant pressure regulating valve 19 in a steam supply line 20 to operating means in the form of a turbocompressor 21, and more particularly, a turbine 22 which discharges steam through a discharge line 23 to a steam condenser 24. A steam condensate pump 25 returns the steam condensate through a return line 26 from the steam condenser 24 to the steam generator 12 for recirculation through the power side of the system. The turbocompressor 21 has flow restricting means in the form of seals, as 27, for retarding leakage of steam and refrigerant from the turbine 22 and the compressor 32, respectively, and water lubricated bearings, as 27", and the steam condensate pump 25 pumps steam condensate through a lubricant water line 28 including a lubricant cooling heat exchanger 29 for lubricating the bearings 27". Leakage from the turbine and compressor, and water from the bearings 27", passes into a chamber 30 and through a drain line 31 to the steam condenser 24.

The refrigerant side of the system includes a refrigerant compressor 32 of the turbocompressor 21. The compressor 32 is drivingly connected with the turbine 22 for passing compressed refrigerant vapor to a refrigerant condenser 33. Condensed refrigerant passes from the refrigerant condenser 33 to a refrigerant subcooler 34 and through a suitable refrigerant flow restricting means 35 into an evaporator or cooler 36, from which the refrigerant vapor is withdrawn by the refrigerant compressor through a suction line 37, thus completing the refrigerant circuit of the system. The cooler includes a water supply sump 38 and provides means for separating water and refrigerant. A chilled water line 39 communicates with a tube bundle 40 in the cooler 36 for carrying a heat exchange medium, here in the form of chilled water, which is cooled by the refrigerant and circulated by a chilled water pump 41 to an area having a cooling requirement. The cooling capacity of the system varies in proportion to the compressor speed.

A cooling tower or condensing water pump 42 circulates tower water through an inlet line 43 to the refrigerant subcooler 34 and into the refrigerant condenser 33 and then the steam condenser 24 and back to the tower through an outlet line 44. A branch line 45 in the condensing water inlet line 43 provides tower water to the lubricant water heat exchanger 29 for cooling the lubricant water, and this branch terminates in the return line 44 to the tower. In general, control of condensing water temperature and flow rate is unnecessary, thus minimizing scaling of condensing surfaces in the condensers.

The control system regulates the cooling and simultaneous cooling and heating capacities of the refrigeration system by varying the steam condenser pressure which is related to the condensing rate of steam discharged into the steam condenser 24. The condensing rate of the steam condenser is regulated by ontrolled blanketing of a first condensing portion or tube bundle 46 with a noncondensible vapor, herein refrigerant vapor, introduced through a refrigerant line 47 from the cooler 36.

The quantity of noncondensible vapor effectively blanketing the first condensing portion 46 of the steam condenser is regulated by a modulating refrigerant flow regulating valve 48 in the line 47. The valve 48 is actuated responsive to leaving chilled water temperature by means of a temperature sensor 49 on a leaving branch of the chilled water line 39. For example, as the cooling load drops, more refrigerant is introduced into the steam condenser 24, thus reducing the steam condensing rate to increase the steam condenser pressure and therefore the temperature of the saturated steam in the condenser, and the turbine back pressure to reduce the turbocompressor power output and in general, the turbocompressor speed.

A purge system withdraws refrigerant from the steam condenser 24, preferably at a constant rate. Herein a constant speed water supply pump 50 in a water line 51 ,recirculates impeller Water from the cooler sump 38 for operating a jet pump 52 in the sump to withdraw noncondensible vapor from the steam condenser 24 through a purge line 53 opening into the throat of the jet pump 52. The water supply pump 50 further provides makeup water for the steam generator 12 through a makeup water line 54 to the steam condenser 24.

Simultaneous heating and cooling, wherein the heating and cooling capacities of the system vary inversely of each other, i provided. A second condensing portion or tube bundle 55 in the steam condenser 24 is maintained effectively free of blanketing by refrigerant vapor to maintain its full condensing capacity and maximum heating of a heating medium, herein water, circulated through the bundle 55 and to a load to be heated by means of a heating water pump 56 in a heating line 57 including a leaving branch 58 to the area having a heating requirement and a returning branch 59 back to the second condensing portion 55.

The refrigerant injected into the steam condenser to blanket the first condensing portion 46 enters the steam condenser through a refrigerant port 60 at the end of the refrigerant line 47 within one end of the steam condenser 24 between the first condensing tube bundle 46 and the second condensing tube bundle 55 adjacent an end of the bundles. A baffle 61 extends between upper and lower portions of the steam condenser between the first and second condensing tube bundle 46 and 55, to prevent the how of fluids therebetween except in a limited area of communication 62 at the refrigerant port 60. The entering steam first flows from the discharge line 23 through a steam condenser inlet port 63 at an end of the condenser 24 opposite the area of limited communication 62, and across the second condensing tube bundle 55, then through the area of limited communication 62 and past the refrigerant inlet port 60, and then past the first condensing bundle 46. The refrigerant vapor entering the steam condenser 24 is drawn across the tubes of the first condensing bundle 46, and in the illustrated embodiment each tube is effectively individually enveloped by a sheath or layer or refrigerant vapor thereby insulating the tubes of the first condensing bundle from the steam to reduce the steam condensing capacity. A condensate chamber 64 of the steam condenser 24 is in communication with the interior of a body shell 65 of the steam condenser through 'a port 66 at the bottom of the condenser and at the same end of the condenser as the steam inlet port 63. The drain line 31, the makeup water line 54 and the condensate return line 26 open into the chamber 64. Thus, the turbocompressor chamber 30, the steam discharge passage 23, the drain 31, and the steam condenser 24 are all at substantially the same pressure, that is, the steam condenser pressure which is normally below ambient atmospheric pressure during normal cooling operation.

The purge line 53 opens into the steam condensate chamber 64 at a-level to withdraw steam condensate from the chamber should the condensate level rise too high. Responsive to a low condensate level in the condensate chamber, a float actuated sensor 67 in the chamber opens a normally closed shutoff valve 68 in the make-up water line 54 from the water supply pump 50, to maintain a minimum level of condensate in the chamber 64.

At high cooling capacity, only a small quantity of refrigerant is in the steam condenser 24 to blanket the first condensing portion 46 so that the steam condenser pressure is low and the temperature of saturated stream in the condenser is correspondingly low. Therefore, the temperature of the water in the second condensing portion 55 is low and little heat is provided for the load to be heated. Conversely, when the cooling capacity is low the heating capacity is normally high.

In the illustrated embodiment, a shell 77 of the refrigerant condenser 33 envelops the steam condenser shell 65 so that refrigerant, which is normally above atmospheric pressure in the refrigerant condenser 33, effectively prevents the entry of ambient air into the steam condenser 24 and insulates the steam condenser during winter heating operation to facilitate maximum heating of the second tube bundle 55. A condensing tube bundle 78 in the refrigerant condenser 33 receives tower water from the refrigerant subcooler 34 and passes the water to the steam condenser first condensing bundle 46.

Responsive to the turbine 22 driving the compressor 32, refrigerant vapor is compressed and passes through a compressor discharge line 79 and into the refrigerant condenser 33 where it is condensed and cooled. The refrigerant condensate flows through a refrigerant condensate line 80 into the refrigerant subcooler 34 from which it passes through the refrigerant flow restricting means 35, here in the form of a float valve unit, and flows through a cooler refrigerant supply line 81 and into a cooler refrigerant inlet 82 extending through a shell 83 of the cooler 36. A suitable equalizer line 84 connects the float valve unit chamber and the refrigerant condenser, for reasons well understood in the art.

The refrigerant inlet 82 opens into a pan 85 spaced above the bottom of the cooler shell 83 which defines the sump 38. The chiller water bundle 40 is in the pan 85 so that during normal cooling operation of the system, the bundle is flooded by boiling refrigerant. As the refrigerant vaporizes, it passes into a refrigerant chamber 86 in an upper portion of the cooler shell 83 above the pan 85. The refrigerant suction line 37 to the compressor 32 opens into an upper portion of the refrigerant chamber 86.

During cooling operation of the system, water in the sump 38 is maintained at least F. above the temperature in the refrigerant chamber 86, so that refrigerant in the sump is a vapor, as is more fully described in my copending United States patent application for a Heating and Cooling System, Serial No. 377,258, filed June 23, 1964. Refrigerant vapor in the sump passes upwardly about a left end wall 87 of the refrigerant pan 85 and into the refrigerant chamber 86 from which it is withdrawn through the suction line 37. Any water in the refrigerant chamber 86 collects on top of the liquid refrigerant in the pan 85 and passes to the left end of the pan from which it flows through a suitable weir or port 88 in the end wall 87 of the pan and into the sump 38. The chilled water tube bundle 40 is spaced inwardly from the left end wall 87 to form a relatively quiet area 89 of liquid refrigerant upon which water in the pan collects. Thus, means is provided for separating water and refrigerant and returning the separated fluids for reuse in the system.

When it is desired to provide only heating, as for winter heating, the condensing water pump 42' is shut off and valve means 90 in the steam supply line 20 to the turbocompressor 21 is adjusted so that the steam bypasses the turbine 22 and is injected through a bypass line 91 into the steam condenser 24 for heating the second condensing portion 55. During Winter heating, the heating capacity of the system is preferably controlled by regulating the modulating fuel valve 16 in the fuel line to the steam generator burner 13.

During winter heating operation, refrigerant may migate into the steam condenser 24, as from the refrigerant condenser 33 or through the turbine drain 31, and must be removed from the steam condenser along with any residual refrigerant therein in order to effect maximum heating of the second tube bundle 55 which provides hot water to the load to be heated. The noncondensible refrigerant vapor is withdrawn through the purge line 53, and the water supply pump 50 is therefore in operation to provide impeller water for the jet pump 52. In order to prevent water from flashing at the jet pump 52, the impeller water must be below the water saturation temperature of the steam condenser 24 and, more particularly, in the steam condensate chamber 64. Therefore, the water line 51 to the jet pump 52 passes through a jet impeller water heat exchanger 92 for cooling the impeller water. A

three-way valve 93 in the return branch 59 of the heating line 57 is adjusted to pass the returning heating water through a line 94 to the heat exchanger 92, from which the heating water returns through a line 95 to the return branch 59 of the heating line 57 and then to the second condensing bundle. The heat exchanger 92 assures a jet impeller water temperature at or very close to the temperature of the heating water entering the steam condenser, and during winter heating operation the water saturation temperature in the steam condensate chamber 64 is necessarily above the returning heating water temperature. During simultaneous heating and cooling operation, the three-way valve 93 .is adjusted so that the returning heating water bypasses the heat exchanger 92 and flows directly into the second condensing bundle 55.

Refrigerant storage means is provided to permit factory charging of the system with refrigerant,'to store refrigerant during servicing of the machine, and for reducing the load on the purge system during winter heating operation at which time the refrigeration system is not in operation. A refrigerant passage line 96 connnects upper portions of a closed refrigerant storage vessel 97 and the refrigerant chamber 86 of the cooler 36. When the turbo compressor 21 is inoperative as during winter heating operation, the pressure in the refrigerant chamber 86 is much higher than during normal cooling operation. For example, during normal cooling operation the cooler may be at a pressure of about 5 p.s.i.g., when the turbocompressor is stopped the pressure rises rapidly, and during heating operation the cooler may be at a pressure of about 50 p.s.i.g. The storage vessel 97 is maintained at a relatively low temperature below the boiling point of the refrigerant so that the refrigerant vapor enters the storage vessel and condenses and remains in the storage vessel. The walls 98 of the storage vessel 97 are exposed to ambient air about the system so that under favorable conditions a temperature below the vapor' point of the refrigerant is thereby maintained in the storage vessel. During winter heating operation, the steam condenser 24 is at a substantially higher temperature than during cooling operation, so that water in the cooler sump 38 is at a higher temperature, in part because of the vapor injected through the purge system is at a relatively high temperature. To assure proper condensing of refrigerant in the vessel 97, the blower 18, which may be on either side of the vessel 97, is connected to pass combustion air through condensing means, here in the form of a tube bundle 99 within the storage vessel, thus assuring a relatively low temperature therein and preheating the air to the burner. It should be noted that the condensing bundle 99 in the storage vessel is so positioned that when the charge of refrigerant is stored therein, a lower portion of the bundle is below the normal predetermined level of liquid refrigerant and therefore immersed in the liquid refrigerant, and the upper portion of the bundle is exposed to refrigerant vapor for condensing the refrigerant vapor.

When the turbocompressor 21 is again operative, the pressure in the cooler 36 drops substantially, so that any refrigerant therein vaporizes and the reduced pressure in the line 96 to the storage vessel, causes the refrigerant to boil out of the storage vessel and pass back into the cooler for circulation through the refrigerant side of the system. The line 96 between the cooler refrigerant chamber 86 and the storage vessel 97 is provided with a normally open shutoff valve 100, when closed for retaining the refrigerant in the storage vessel, as during servicing or shipping of the machine. Suitable pump-down connections may be provided.

The storage vessel 97 is positioned at an elevation above the cooler 36, and more particularly above the refrigerant pan 85, so that liquid refrigerant and any water condensed in the storage vessel may be drained therefrom into the pan through a drain line 101. The drain line 101 has a normally closed shutoff valve 102 for holding the liquids in the vessel.

While this invention has been described and illustrated in a preferred embodiment, it will be understood that the invention is not limited thereto since it may be otherwise embodied within the scope of the following claims.

I claim:

1. A cooling system comprising a cooler, operating means operable for circulating refrigerant through said cooler during normal cooling operation of the system, a cooler vessel, passage means connecting said cooler and said vessel for the passage of refrigerant vapor from said cooler into said vessel when said operating means is inoperative and for the passage of refrigerant from said vessel into said cooler when said operating means is in operation, and means in said vessel for condensing refrigerant vapor and thereby retaining the refrigerant in the vessel when said operating means is inoperative.

2. The system of claim 1 wherein said cooling medium is air, and air circulating means for circulating air through said condensing means to condense the vapor.

3. A method of passing refrigerant between a refrigerant circuit having a cooler and a storage vessel in communication with the cooler, and a compressor operative for passing refrigerant to the cooler and withdrawing refrigerant vapor from the cooler to provide a low pressure area in the cooler during normal cooling operation of the circuit, comprising the steps of stopping operation of the compressor, thereby stopping normal withdrawal of refrigerant vapor from the cooler to increase the pressure in the cooler above the pressure in the vessel for the flow of refrigerant vapor from the cooler into the vessel, and regulating the temperature in said vessel below the boiling point of the refrigerant, thereby condensing and retaining the refrigerant in the vessel while the compressor is inoperative.

4. The method of claim 3, and the additional step of starting the compressor in operation, thereby reducing the pressure in the cooler below the pressure in the vessel for the flow of refrigerant from the vessel to the cooler and circulation in the refrigerant circuit.

References Cited by the Examiner UNITED STATES PATENTS 10/1944 Urban 62l49 8/1965 Andersen l6562 

3. A METHOD OF PASSING REFRIGERANT BETWEEN A REFRIGERANT CIRCUIT HAVING A COOLER AND A STORAGE VESSEL IN COMMUNICATION WITH THE COOLER, AND A COMPRESSOR OPERATIVE FOR PASSING REFRIGERANT TO THE COOLER AND WITHDRAWING REFRIGERANT VAPOR FROM THE COOLER TO PROVIDE A LOW PRESSURE AREA IN THE COOLER DURING NORMAL COOLING OPERATION OF THE CIRCUIT, COMPRISING THE STEPS OF STOPPING OPERATION OF THE COMPRESSOR, THEREBY STOPPING NORMAL WITHDRAWAL OF REFRIGERANT VAPOR FROM THE COOLER TO INCREASE THE PRESSURE 